THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Art. I. — On the Emission of Electricity from the Induced 

 Activity of JRadium • by William Duane.* , 



1. In the winter of 1905-1906, I made some experiments 

 on the decay of the induced activity of radium, using as a 

 means of measurement the quantity of electricity carried by 



r*P 



Connections : p, to pump ; e, e, to earth ; I, to electrometer ; t, to battery. 



the a and /3 rays instead of the ions produced by them. Up 

 to that time this method of studying the decay curves had not 

 been employed. A description of the experiments was pre- 

 sented at a meeting of scientists held at the University of 

 Colorado in the spring of 1906, a brief resume of which 



* Translation by the author of a paper published in " Le Eadium " (vol. v, 

 p. 65, March, 1908), entitled : Sur remission d'electricite par la radioactivite 

 induite du radium. 



Am. Jour. Sci.— Fourth Series, Vol. XXVI, No. 151.— July, 1908. 

 1 



